// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/renderer/device_sensors/device_light_event_pump.h"

#include "base/time/time.h"
#include "content/public/renderer/render_thread.h"
#include "device/sensors/public/cpp/device_sensors_consts.h"
#include "third_party/WebKit/public/platform/WebDeviceLightListener.h"

namespace {
// Default rate for firing of DeviceLight events.
const int kDefaultLightPumpDelayMicroseconds = base::Time::kMicrosecondsPerSecond / device::kDefaultAmbientLightFrequencyHz;
} // namespace

namespace content {

DeviceLightEventPump::DeviceLightEventPump(RenderThread* thread)
    : DeviceSensorMojoClientMixin<
        DeviceSensorEventPump<blink::WebDeviceLightListener>,
        device::mojom::LightSensor>(thread)
    , last_seen_data_(-1)
{
    pump_delay_microseconds_ = kDefaultLightPumpDelayMicroseconds;
}

DeviceLightEventPump::~DeviceLightEventPump()
{
}

void DeviceLightEventPump::FireEvent()
{
    DCHECK(listener());
    DeviceLightData data;
    if (reader_->GetLatestData(&data) && ShouldFireEvent(data.value)) {
        last_seen_data_ = data.value;
        listener()->didChangeDeviceLight(data.value);
    }
}

bool DeviceLightEventPump::ShouldFireEvent(double lux) const
{
    if (lux < 0)
        return false;

    if (lux == std::numeric_limits<double>::infinity()) {
        // no sensor data can be provided, fire an Infinity event to Blink.
        return true;
    }

    return lux != last_seen_data_;
}

bool DeviceLightEventPump::InitializeReader(base::SharedMemoryHandle handle)
{
    if (!reader_)
        reader_.reset(new DeviceLightSharedMemoryReader());
    return reader_->Initialize(handle);
}

void DeviceLightEventPump::SendFakeDataForTesting(void* fake_data)
{
    double data = *static_cast<double*>(fake_data);

    listener()->didChangeDeviceLight(data);
}

} // namespace content
